1. Field of the Invention
The present invention relates to a mouse with a wheel, for controlling an image on a display device, and more particularly to a mouse with a wheel, which has a simple and non-photo-mechanism for measuring the direction and amount of rotation of the wheel.
2. Description of the Related Art
A mouse is frequently used as an auxiliary input device of a computer. In recent years, there has been a demand for mice that provide a variety of functions. The use of mice with a wheel, for scrolling an image on a display device are becoming widespread. The wheel is mounted so that a portion of the circumference thereof is exposed from a top cover of the mouse. When a user rotates a peripheral edge portion of the wheel with his or her finger in one direction, the image is scrolled upward or downward depending on the direction in which the wheel is rotated, and by an amount depending on the amount by which the wheel is rotated. There is a type of mouse having a mechanism that allows scrolling of an image as a result of rotation of a mouse ball when a user presses the wheel downward.
FIG. 3 illustrates a wheel mechanism used in a conventional mouse.
In FIG. 3, a mouse 100 comprises a wheel 101. A portion of a circumferential portion 102 of the wheel 101 is exposed to the outside from an opening in a top cover (not shown). A plurality of slits 105 are formed at a hub 103 of the wheel 101 so as to extend radially from a rotary shaft 104.
The rotary shaft 104 of the wheel 101 is axially supported by a rocking arm 107 which can rock upward or downward with a rocking shaft 106 as a center. The rocking arm 107 is biased upward by a spring (not shown). A mode change-over switch 114 is mounted below the rocking arm 107. It is provided to bring a mode change-over electrical circuit into electrical conduction when the user presses the wheel 101 downward with his or her finger and causes the mode change-over switch 114 to come into contact with the rocking arm 107.
An optical sensor comprising a set of a light-emitting element 111 and a light-receiving element 112 is provided on a circuit board 110 of the mouse 100. The light-receiving element 112 comprises two light-receiving diodes arranged side by side. After the passage of beams 113 emitted from the light-emitting element 111 through slits 105, the two light-receiving diodes successively receive the beams 113.
An image-controlling ball mechanism 120 (not described in detail) is mounted to the mouse 100.
When the user rotates the wheel 101 of the mouse 100 with his or her finger, the slits 105 of the wheel 101 cause pulsation of the beams 113 emitted from the light-emitting element 111, so that the beams 113 reach the light-receiving element 112 as pulses of light. Therefore, when one pulse of light is defined as one count, the amount by which the wheel 101 is rotated is converted into number of counts in digital form, and the result is sent to a computing device. On the other hand, by detecting the order in which the two light-receiving diodes of the light-receiving element 112 receive light, the direction of rotation of the wheel 101 is determined. From the direction of rotation and the number of counts of rotation of the wheel 101, the computing device causes an image to be scrolled either upward or downward by a required amount.
On the other hand, when the user presses the wheel 101 downward with his or her finger, the mode change-over switch 114 is brought to a state allowing electrical conduction, and the rotation of the ball mechanism 120 allows scrolling of an image, so that the function of the ball mechanism 120 can be changed.
The conventional mouse allows an image to be easily scrolled by the above-described wheel mechanism. However, this mechanism has the following problems. The properties of the light-emitting element 111 and the light-receiving element 112 must match and a light path must be precisely adjusted, making the assembly operation complicated. In addition, the unit including the photo-elements are expensive, resulting in high manufacturing costs. Further, since the photo-unit is always on during input operations, a large amount of electrical power is consumed.
To overcome the above-described problems, it is an object of the present invention to provide a mouse with a wheel, having a simple and non-photo-mechanism for measuring the direction and amount of rotation of the wheel.
To this end, according to the present invention, there is provided a mouse with a wheel, comprising:
a gear coaxially mounted to a rotary shaft of the wheel;
a rocking member in which rocking arms extend from both sides thereof with a rocking shaft formed parallel to the rotary shaft of the wheel as a center;
a pawl member mounted to the rocking member, the pawl member being biased so as to engage the gear; and
contact switches disposed at locations that allow the contact switches to come into contact with the rocking arms corresponding thereto, in which when the rocking member rocks to one side, the corresponding contact switch comes into contact with the corresponding rocking arm in order achieve electrical conduction;
wherein the contact switches are connected to a counter circuit for determining an amount of rotation of the wheel.
In the mouse with a wheel, when a user rotates the wheel in one direction with his or her finger, the gear coaxially mounted to the wheel rotates in the same direction, causing a crest of the gear to push the pawl member, biased so as to engage the gear, in the direction of rotation. This causes the rocking member to rock in one direction, causing the corresponding arm to push the corresponding contact switch disposed at the location allowing it to contact this arm. When the corresponding contact switch contacts the arm, this switch is brought to a state allowing electrical conduction. When the biased pawl member moves over a crest of the gear as a result of further rotation of the wheel, the rocking member returns to its neutral position, whereby the contact switch is brought to a state not allowing electrical conduction.
Since the contact switches are disposed so that they can contact their corresponding rocking arms, and the contact switches are connected to corresponding counter circuits, it is possible to detect the direction of rotation of the wheel based on which counter circuit is in electrical conduction. In addition, since the corresponding counter circuit is brought into or out of conduction each time the pawl member moves over a crest of the gear, when a pulse is defined as one count, the amount by which the wheel is rotated can be detected as number of counts in digital form. A computing device computes the detected direction and amount of rotation of the wheel in order to the control the image on a display device such that the image is scrolled, for example, either upward or downward by a required amount.
Although not exclusive, at least one end portion of the rotary shaft of the wheel may be made vertically movable, the movable end portion of the rotary shaft being biased upward; and the mouse may further comprise a mode change-over switch, disposed below the movable end portion, for changing a function of a ball of the mouse.
In this case, when a user presses the wheel downward with his or her finger, the movable end portion of the rotary shaft of the wheel moves downward to push the mode change-over switch and bring the mode change-over circuit into electrical conduction. When the user stops pressing the wheel, the movable end portion returns to its initial position to bring the mode change-over switch into the state not allowing electrical conduction. Therefore, when the mouse is moved and the ball is rotated while the wheel is pressed downward, it is possible to change ball functions to allow the image on the display device to be scrolled by a predetermined amount not only in the vertical directions, but also in horizontal directions and oblique directions.